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Extreme Temperatures and Your Horse Trailer: How to Keep Your Horse Safe During Hot Summer Trips

Last updated July 5, 2024 by Brad Heath

The middle of summer might seem like the perfect time to load up your horses and head out for a ride. The sun is shining, the birds are singing, and you’re excited to hit the trail and make the most of a beautiful summer day.

But, while you’re singing along to your favorite songs and enjoying the air conditioning, your horse is in the back of your trailer. And in the heat of the summer, he might not be doing too great. Trailering your horse on a hot summer day can be very dangerous. Some horse trailers aren’t well insulated and don’t have enough ventilation, which can lead to overheating and dehydration.

So, if you’re taking your horse to a competition on a hot day, or if you do decide to hit the backcountry trails, both you and your horse need to be ready for hot temperatures. If you’re well prepared, you’ll have a safe and enjoyable trip. And your horse will be comfortable and ready to ride or perform when you get to your destination.

What Happens Inside Your Horse’s Body in the Heat?

Before diving in to the dangers of overheating and dehydration, it’s important to know exactly what is happening in your horse’s body on a hot summer day.

When a horse gets hot, the body’s natural response is to get rid of the heat, in order to cool the horse down and return the body to normal temperature. To do that, your horse’s body goes through several changes. The goal is to transfer heat from the core to the surface of the body, where it can leave the body and evaporate into the air.

So first, the horse’s heart rate increases, which improves blood flow, but transfers it to other parts of the body rather than just the vital organs. Then, the horse will start panting in an effort to bring cooler air into his body. Finally, while trying to cool down, the horse will start sweating, which causes fluid loss from his body (1).

These are all normal mechanisms that occur in your horse’s body to keep him cool and to maintain a safe body temperature. However, when your horse’s body is doing all those things and still can’t cool down, the body goes into overdrive – his heart rate increases dramatically, he starts sweating uncontrollably, and he starts panting intensely.

When this happens, your horse can become dehydrated or overheated, and in extreme cases, blood flow to his heart, brain, and lungs could shut down completely.

The Two Major Dangers When Trailering Your Horse in the Summer 

horse trailer safety

On a hot summer day, when your horse is outside grazing or walking around, his cooling mechanisms work well. When your horse’s body sends the heat from the core to the surface, heat can be carried away from your horse as a cool breeze blows by. When your horse sweats, the sweat turns into a vapor that dissolves into the open environment around him.

However, in a trailer, those normal cooling mechanisms are hampered by the small, enclosed environment. When you horse sweats or radiates heat away from his body in the trailer, there’s nowhere for the heat to go. The heat and the vapor from your horse’s sweat builds up inside the trailer and your horse can’t cool down (1).


When this happens, your horse is likely to experience dehydration. To maintain a healthy body temperature, your horse needs plenty of fluid in his system. When he sweats, that fluid is lost, and if he’s not drinking water while in the trailer, there’s no way for him to replace the lost fluids.

Dehydration is dangerous because it can lead to kidney failure and because it’s connected to overheating and heat stress. You can tell if your horse is dehydrated if you check their gums and their upper lip. A healthy, hydrated horse will have pink, moist gums. To check if your horse is dehydrated, press your thumb on his upper lip for a second. It should turn white then quickly turn pink again. If it takes more than a few seconds to turn pink, your horse could be dehydrated.

You can also quickly swipe your finger along your horse’s upper lip. If it’s moist with saliva and shiny, your horse is well-hydrated. If your finger is dry and their upper lip is white or purple, your horse is probably dehydrated (2).

Another way to test your horse’s hydration levels is to do what’s called a skin-pinch test. On your horse’s neck, gently pink some of their skin with your fingers to form a small “tent.” If the tented area snaps down quickly, your horse is not dehydrated. However, if the tented area is slow to go back to normal, your horse is dehydrated.

Overheating and Heat Stress

If your horse is dehydrated for a long amount of time, it’s likely that they will start overheating and experience heat stress. If your horse is in hot temperatures for an extended period of time, he could be at risk of experiencing problems like heatstroke, muscle spasms, and cholic.

Some common sings of heat stress are: increased heart and breathing rate, extreme sweating, tiredness and lethargy, droopy ears, and dehydration. You can also try the skin-pinch test on your horse to see if they are overheated – if the tent area lasts more than several seconds, your horse is overheated.

Overheating is very dangerous because if left untreated, your horse’s body temperature can keep rising and it can turn into heat stroke. A horse that is experiencing heat stroke might collapse from exhaustion and start convulsing. This can be fatal for horses (3).

In Case of Emergency – What to Do if Your Horse is Overheating

A horse’s normal body temperature is 98-101 degrees Fahrenheit. If that temperature rises to over 103 degrees, your horse is overheating. If that happens, here are the steps you should take to cool him down:

  1. Lead your horse out of the horse trailer to a shaded area, preferably somewhere with a breeze and access to water.
  2. Spray your horse with water, or if a hose is not available, sponge cold water onto your horse. Make sure to scrape off the water after you hose down your horse; the water will absorb his body heat, so getting rid of warm water before spraying your horse again will help him cool down faster.
  3. Put rubbing alcohol on your horse’s neck, chest, and back leg muscles after you hose him down. This will help evaporate the heat and cool him down even more.
  4. Give your horse cold water to drink. Check your horse’s temperature to see if it gets better, if their temperature doesn’t go down, it’s time to call the veterinarian. (1)

If your horse’s body temperature rises to over 105 degrees, your horse is very hot and at danger of heat stroke. In this situation, you can use ice water to cool your horse down. Focus on putting ice water on the horse’s head, neck, back, and rib areas. Those areas have more blood vessels, which will help your horse return to a normal and safe temperature faster (4).

Expert Opinion: Dr. Alexandra Tracey on How to Keep Your Horse Safe in Hot Weather

It’s always better to prevent dehydration and heat stroke in horses rather than try to fix it after discovering the problem. Even though trailering horses on a hot day is a risky activity that could put your horses at risk of overheating, there are many things you can to do prevent catastrophes and make travel as safe as possible for your horses.

Recently, we talked with Dr. Alexandra Tracey DVM, DACVS-LA from Palmetto Equine Veterinary Services in Townville, South Carolina to discover the best ways to keep horses safe while traveling in high temperatures.

She said that once you get on the road, make sure to carefully monitor your horse. Watch out for signs of heat stress, such as “extreme sweating, flared nostrils, and increased breathing rate.” Dr. Tracey explained that when heat stress gets worse, the horse actually stops sweating and he becomes depressed. It’s important to note that at this point of distress, the horse will probably not even want to drink water.

So, what can you do to prevent this? Dr. Tracey recommends staying away from trailering on high heat and high humidity days – especially when temperatures are over 90 degrees. She says that “during the summertime, you should take advantage of the cooler temperatures in the morning and start travel as early as possible.”

The most important way to prevent overheating while traveling is to have a lot of airflow in the trailer. All vents and side windows should be open while traveling in hot temperatures to create wind inside the trailer. She says, “when you are traveling, keep moving as much as possible to create airflow for your horse – avoid high traffic areas where you have to stop and wait a lot.”

She also noted that because you’ll be creating a lot of airflow, that will cause all the hay and dust in your trailer to move around as well. To make sure your horse is comfortable and calm, you might want to put a fly mask on your horse to protect his eyes and avoid irritation. However, in the summer, that should be the only type of gear you put on your horse. Avoid traveling in shipping boots and sheets, because they only make your horse even hotter on high temperature days.

Prepare Before Loading Your Horse in the Trailer

Dr. Tracey told us that it’s not just what happens in the trailer that can determine whether your horses overheat or not – what you do before loading into the trailer is just as important. She stressed the importance of hydration days before leaving on your trip. Dr. Tracey said that you can add water to your horse’s hay or grain ration to make a mash or a soup. This increases their water intake and can be especially helpful for horses that don’t like drinking a lot of water.

preparing horse for travelShe also mentioned the importance of oral electrolyte supplements. When a horse sweats, he loses electrolytes, which can cause tiredness. She said “oral electrolyte supplements can be in the form of a gel or a paste, and you can administer them similar to how you would give your horse a dewormer.” You can add the electrolytes directly to the horse’s feed the night before and the morning of a big trip.

But she doesn’t recommend adding the supplement to your horse’s water. Sometimes, it can give the water a funky flavor and if your horse is picky, it might not want to drink it. And, the last thing you want before a big trip is a horse that doesn’t want to drink water. That’s why it’s best to add it to the feed, so your horse eats it without even noticing.

You can even make your own electrolyte supplements – since electrolytes are really just salt, they’re super easy to make. All you have to do is “mix three parts sodium chloride (normal table salt) with one part potassium chloride (“lite salt”) and give your horse two to four tablespoons per day” (1).

How Hot is Too Hot?

Really, the best way to keep your horse safe is to avoid trailering in any sort of extreme temperatures. Dr. Tracey recommends avoiding trailering on days that are hotter than 90 degrees. However, sometimes travel is essential and travelling on hotter days is necessary.

But, when it comes to heat, temperature isn’t the only factor for your horse. You must also take into consideration the humidity levels where you are going to be traveling. Both the air temperature and the relative humidity affect how comfortable your horse is in the trailer and how likely he is to overheat or suffer from heat stress.

Air Temperature + Relative Humidity

You can calculate a day’s heat score by adding the air temperature in degrees Fahrenheit to the percentage of relative humidity. For example, if today’s temperature is 80 degrees with 65% humidity, today’s heat score is 145 (80+65=145).

This straightforward equation can give you a good idea of how hot your horse will be on any given day while riding, working, or traveling. If the heat score is less than 130, your horse will be able to properly cool himself without any problems, so you won’t have to worry at all. If the heat score is 130-150, your horse’s cooling efficiently is decreased, but you’re still safe to travel.

When the heat score reaches numbers greater than 150, your horse is likely to be very uncomfortable because his cooling mechanisms will be greatly reduced. If the heat score is greater than 180, the condition can be fatal if your horse is stressed.

It’s important to remember also that if the relative humidity is equal to or greater than the temperature, you should be extremely cautions, even if the temperature is lower than what you would consider a hot temperature (for example, 75 degrees with 85% humidity). Humidity can make a huge difference in how hot it feels outside for your horse, so don’t take any chances (5).

What Trailers Are Best for Maintaining Temperature?

When it comes to maintaining a safe temperature for your horse, all trailers are NOT the same. Trailers that have large windows and open sides are much better because they facilitate airflow and keep the trailer well ventilated. If your trailer has vents that you can open and close, when you travel on hot days, you should open all the vents and windows that aren’t directly in front of your horse’s face.

rumber floors

The type of flooring in your trailer can also make a big difference in how hot it gets inside of your trailer. Trailers with aluminum metal floors transfer all the heat from the asphalt roads up into your trailer and directly onto your horse’s legs and body. Instead of aluminum metal floors, when choosing a trailer, look for one with lumber or synthetic rumber floors that prevent heat transfer.

The roof of your trailer can also influence the temperature of your trailer. Try to avoid trailers that have mill-finished aluminum roofs – this type of roofing material is very heat conductive. On hot summer days, trailers with aluminum roofs soak up the sun’s rays and heat up the inside of the trailer very quickly – just like a hot oven.

The best roofing materials are double layered insulated materials that are painted white to reflect the heat, instead of absorb it. All Double D Trailers have a special Safebump roofing system made up of fiber composite materials that not only prevent heat absorption, but also are flexible in case your horse rears up and bumps his head on the top of your trailer.

Try to choose a trailer that has roof vents above where your horse will be standing. This helps increase air flow to your horse’s body so he can stay cool. Roof vents and large windows that can be easily opened are essential for helping your horse stay cool on the road.

One of the main differences between a trailer that help your horse stay cool and a trailer that turns into an oven on hot days is the type and quality of insulation they have. Quality insulation can make all the difference in keeping your horse at a safe and comfortable temperature during travel.

And, it’s not just living quarters horse trailers that should have reliable insulation – every horse trailer should have quality insulation installed to protect your horse from extreme temperatures, both during the cold days in the winter and the blistering hot days in the summer. Trailer insulation is super important for your horse’s comfort and safety on the road.

Check out this aluminum horse trailer review.

Trailer Insulation – The #1 Factor in Keeping Your Horse Safe

It’s clear that the most important reason why your trailer should have good insulation is to control the temperature inside your trailers. Just like how insulation in a house helps prevent your home from getting too hot or too cold, insulation in your trailer does the same.

Many trailer brands build their trailers with just a single layer of metal surrounding the main cabin area. This aluminum sheet metal heats up quickly and soon the heat from the outside transfers directly to the inside of your horse trailer – and onto your horse. In an uninsulated trailer, temperatures can sky-rocket on hot days.

trailer construction

In a trailer with good insulation, the sidewalls of the horse cabin area are built with two layers of material, which helps to maintain a much safer inside temperature for your horse. Double D Trailers are built with an outer layer of 0.04 gauge aluminum metal, and an inner layer made of 16 gauge Galvalite metal in the sidewalls. The roof is made of a single piece of fiber-composite material, which is one of the best types of insulations and often used in home construction.

Galvalite metal, although it looks very similar to aluminum, is actually 5 times stronger and more durable than aluminum metal. Why? Because it’s made of zinc, a super strong metal that not only better protects your horse in the case of an accident, but also keeps them safe from extreme temperatures as well.

Is the Front Tack Area of Your Trailer Insulated?

Trailer insulation isn’t just important for the horse cabin area of your trailer – it’s important for the front of your trailer where the sleeping quarters or dressing room is too. You might be thinking, well, obviously! But many trailer manufacturers try to save money by only putting a single layer of metal to insulate those areas – making it uncomfortable for you as well.

trailer insulation

When choosing a trailer, look at the inside of the walls in the dressing room or sleeping quarters area. You can easily tell if the area is well insulated or not by taking a quick peek at these areas. If you can see vertical metal supports on the walls, that means the front area is not insulated. If the walls are smooth, then the trailer is well-insulated and you’ll be much more comfortable.

Because so many trailer manufacturers think that most people don’t spend much time in the front tack areas, they decide not to take the extra time and money to insulate them. That’s why it’s so rare to find a trailer with a well-insulated front area.

However, Double D Trailers do have a high-quality well-insulated front tack area, even on bumper pull trailers. Brad Heath, owner of Double D Trailers, explains, “people do spend time in the front area of the trailer, especially in gooseneck trailers. People will camp out and sleep in the trailer, which is why it’s super important for that area to be just as well insulated as the rest of the trailer.”

Trailer Insulation Does More Than Just Maintain Temperature

Trailer insulation isn’t just important for maintaining temperature – it also plays a huge role in helping your horse stay calm and comfortable while on the road. Having a well-insulated trailer can reduce roadway noise and better protect your horse while traveling.

Quieter, More Comfortable Travel for Your Horse

When your horse is stressed, anxious, or scared, his body releases a stress hormone called cortisol. His heart rate, blood pressure, and breathing increase and your horse enters “fight-or-flight” mode. Obviously, if your horse becomes stressed out while in the trailer, he has no way to escape, but he could start bucking, rearing, or pawing – which could cause him to hurt himself while in the trailer.

For your horse, traveling in an uninsulated trailer just adds to the stress he’s already dealing with. Honking cars, motorcycle engines, and the sounds of the highway are all loud noises that can put your horse on edge. And in an uninsulated trailer – those sounds are even louder.

Brad shared that “in single skin uninsulated trailers, there’s just one layer of sheet metal in between your horse and the road – the metal in the horse compartment shakes, rattles and vibrates. It gets so loud that sometimes, it sounds like someone is on the outside of the trailer banging on the side walls with their hands!”

For you horse, all the loud and sudden noises can cause stress, and make for a very uncomfortable ride. After being stressed out on the whole trip, your horse will arrive at the competition nervous and not ready to perform in your event or show. And next time you try to load him into the trailer, he’ll remember the stressful trip and won’t want to get in. It creates a vicious, stressful travel cycle that isn’t enjoyable for you or your horse.

But, with a well-insulated trailer, the double layer of material on the trailer walls actually decreases the amount of outside noise that gets through to your horse. In a Double D Trailer, the insulated roof, the double-layered walls, and the insulated Rumber flooring all work together to dampen the outside noise of the road. Your horse will be able to have a much quieter and much more enjoyable ride to your destination.

Insulation That Delivers More Protection and Strength

In addition to keeping your horse at the right temperature and minimizing the harsh sounds of the road, insulation also makes your trailer stronger and more durable – protecting your horse from danger while in the trailer.

best trailer insulation

An insulated trailer that’s double-walled creates a stronger barrier between your horse and the road. That way, if you horse gets spooked and rears up or kicks the trailer wall, his hoof or leg won’t be able to break through the wall like it would on a single-layered trailer. A well-insulated trailer creates a protective cage around your horse, keeping him safe not only from extreme temperatures, but also from dangerous sharp material that your horse could easily kick though and scrape up his leg.

Double D Trailers all use unique Z-Frame technology to protect your horse in the case of a trailer accident. The zinc-alloy metal material that the frame is made out of is super durable to best protect your horse and last for years and years.

Keep Your Horse Cool and Comfortable in Your Trailer – Even on Hot Summer Days

So, when traveling with your horse, make sure you have a well-insulated trailer with open widows and vents to give your horse the airflow he needs to stay cool on a hot day. If it’s possible, try to get an early start on your journey, as it’s always best to transport your horses during the coolest part of the day. Never park your trailer in direct sunlight while your horses are inside or leave them in an unmoving trailer for long periods of time.

Make sure there’s water available for your horses to drink inside your trailer. Since it’s hot, they’ll be sweating and loosing liquid quickly. Having familiar drinking water inside the trailer will help keep them from becoming dehydrated or stressed from the heat.

Having a quality trailer is the best way to keep your horses safe on the road. A flimsy aluminum trailer will heat up like an oven in the summer sun, but a well-insulated trailer will protect your horse from danger on the road and provide a much more comfortable and calmer journey for you and your horse. Check out this video Brad did in an aluminum trailer to show just how fast temperatures can escalate in an uninsulated trailer.

Double D Trailers have special technology designed to keep your horse cool and safe while on the road. To learn more about Double D Trailer’s special Z-Frame technology and how it works to protect your horse while on the road, check out this article, or take a look at what Double D Trailer owners have to say about our trailers.

If you have any other questions about trailer insulation or temperatures, don’t hesitate to contact Brad Heath, he’ll be more than happy to answer any questions you might have.

Check out this video to learn more on how to keep your horse cool while trailering.


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